I have realized that in old digital cameras, unique detectors help to aim automatically. Those kind of sensors of some camcorders change in in the area of contrast, while others use a beam with infra-red (IR) light, specifically in low lighting. Higher standards cameras often use a mix of both programs and could have Face Priority AF where the digicam can 'See' the face while keeping your focus only upon that. Thanks for sharing your ideas on this web site.